I have always felt terrible, mostly stomach and abdomen pain, always changing types of pain, severity, and location. I went to a specialist, and after doing a colonoscopy and a gastroscopy, nada. Maybe a case of IBS. I have also been dealing with anxiety and depression for about a year, and a hypothyroid. But recently, there has been pain in my lower abdomen, almost like a dull burning. Sometimes I get this pain while masturbating...as odd as that sounds. I'm very underweight (22 years old, 5"7, and 112 lbs.). Im trying a weight gain diet, and in the first few days, I was reading 118 on the scale, so technically, I gained 6 pounds in like, 3 days, which is a little odd. After not eating as much yesterday, for a little break (I was with my girlfriend), and after checking today, i'm back down to 112lbs. How can a human lose 6 pounds in like a day? I don't lose any more. I stay at this weight. With the relentless pain, the futile attempt at weight gain, the anxiety, the hopelessness, it's becoming a chore to simply get out of bed. I need help. Maybe someone can shed light on this situation?